Tire reinforcement fabric



United States Patent inventors n- Young [56] References Cited Akron, Ohi UNITED STATES PATENTS Mlh KW Gem? 1,875,445 9/1932 Hall 139/426 pp 755,542 3,371,475 3/1968 Gorrafa 57 140 Flled d QZB- J 3:: 3,395,744 8/1968 Wolfet a1. 152/358 Patente 1 Assignee The Goodyear Tire & Rubber Company FOREIGN PATENTS Akronohio 596,855 4/1960 Canada ,57/140(BUX) afion 0mm, 697,467 11 1964 Canada 152/359 610,096 10/1948 Great Britain 57ll40(BUX) 1,044,230 9/1966 Great Britain .1 139/426 I Primary Examiner-James Kee :35 1 Drawing Fig Attorneys-F. W. Brunner and RS. Washburn US. Cl 139/426,

53 ABSTRACT: A tire cord fabric with improved resistance to Int. Cl D03d 15/00 webbing and Splitting during adhesive treatment and during .D 2g 3606 drying and stretching as well as in handling and shipping, in- Fickl 0f 139/426 eludes warp cords of high strength material such as polyester 1 57/1401 152/35710 359; and weft or filling threads composed of a blend of polyester 161/90 to 92 fiber and cotton fiber.

111111111 111 I 11111111111111111111111111 1' ""11111 11 1 T I 1 1' HM I 11! l 11 l1 f '1' 1' 1 1"1'1 1'1'1" 11111 'lll "M 51' W'MI 'll 11" 11 ll 11.11.111.111.1'11'1'1'11.'1.1'1'1'1.1"!i11'll' '1 I j I l I x LL I I Maw AGENT TIRE REINFORCEMENT FABRIC The foregoing abstract is not to be taken as limiting the invention of this application, and in order to understand the full nature and extent of the technical disclosure of this application, reference must be made to the accompanying drawing and the following detailed description.

The present invention relates to cord fabric for reinforcement of pneumatic tires and particularly to a tire reinforcement fabric including an improved weft yarn or fill thread.

Tire reinforcement fabric for use in reinforcement of pneumatic tires is conventionally made with warp cords or strength members extending parallel to one another in a common plane and with relatively weak weft threads generally woven over and under successivewarp cords so as to maintain the parallelism and spacing of the cords in the plane of the fabric. This is the simplest and most economical method of forming such fabrics. There have been, however, disadvantages accompanying the use of weft threads and repeated attempts have been made to provide improvement in maintaining the relationship of the warp cords in cord fabrics throughout their processing prior to use of the fabric in pneumatic tires.

The weft threads or yarns perform no useful function in a completed tire and may be detrimental if the warp cords are not uniformly permitted to assume their correct circumferential or lateral positions and spacing when, for example,

the tire is shaped from cylindrical to the generally toroidal shape of a completed pneumatic tire.

Tire cord fabric, after the weaving of warp cords and weft threads, is conventionally subjected to processing which includes application of adhesives in either aqueous or solvent solutions and exposure to relatively high processing temperatures. The fabric is also subjected to considerable tension one or more times during its processing. Before the fabric is incorporated into a tire it is also generally coated with uncured rubber compounds, as by calendering between rolls so that the rubber compound completely surrounds and adherently covers the warp cords of the fabric.

A particular difficulty experienced in treating tire cord fabric heretofore available has been the tendency of adhesives to cause the warp cords to adhere to each other, as well as to bridge or fill the spaces between adjacent cords. When such bridging or webbing occurs, the individual cords are restrained from assuming their proper spacing during subsequent processing or during the building and shaping of the tire. Rubber compounds are prevented from surrounding the individual cords.

Heretofore, weft threads employed in tire reinforcement fabrics have been generally of cotton yarn. It has also been proposed to use yarns or filaments of organic esters, or ethers of cellulose, having low or suppressed extensibility, but such that the weft threads could be dissolved out or absorbed into surrounding compounds from the fabric either prior to or during the vulcanization of the assembled tire. A further proposal has been to use, as weft threads, continuous filaments of highly extensible material such as rubber or rubberlike materials, or nonoriented crystalline synthetic polymers prepared to be extensible by from 50 to several 100 percent.

It has been found that none of the materials heretofore used ,or proposed as weft threads for use in tire reinforcing fabrics have been able fully to satisfy the requirements of controlling the parallelism and spacing of the warp cords during the processing referred to above, particularly as applied to polyester tire reinforcement fabrics.

It is an object of the present invention to provide an improved tire reinforcement fabric including novel weft threads capable of maintaining uniformity of the weave of the fabric. A further object of the invention is to provide a weft thread or yarn having improved performance under exposure to heat and to the stresses encountered in processing the reinforcement fabric. An additional object of the invention to is provide a tire reinforcement fabric having warp cords comprising continuous filaments of polyester and weft or pick threads comprising a yarn blended of noncontinuous or staple fibers of polyester and staple fibers of cotton.

Other objects and advantages will become apparent or will be particularly pointed out in the description herein of particular embodiments illustrative of the invention.

These objects are achieved in accordance with the present invention by the provision of a tire reinforcement fabric having warp cords extending in a common plane parallel to one another in a first direction, and weft or filling threads arranged transversely with respect to the first direction, the weft threads comprising a yarn blended of cotton fiber and of short discontinuous lengths of synthetic polymeric filaments.

The accompanying drawing is a diagrammatic view of a reinforcement fabric embodying the principles of the invention.

In the drawing, the fabric 10 comprises a plurality of warp cords 12 which extend longitudinally in the fabric along an indefinite running length thereof and which provide the reinforcement strength members in a tire or in a cord-reinforced rubber article. The cords 12 generally comprise aplurality of yarns each having a multiplicity of continuous filaments plied or twisted together to form the cord. The filaments of the cords may be of any material suitable for use in reinforcement in pneumatic tires and the like. In the practice of the present invention cords comprising filaments of a polyester are found particularly useful.

The weft threads 14, also called pick, filling, or fill threads or yarns, are woven alternately over and under adjacent cords throughout the width of the fabric from selvage to selvage thereof. Individual weft threads in the fabric 10 are spaced about one-quarter inch to as much as 1 inch from each other along the running length of the fabric. Because weft threads must be readily cut or broken for building a tire, the tensile strength of weft yarns is desirably limited to a low value and are small in size.

In accordance with the present invention, the weft threads 14 comprise a single spun yarn blended of short lengths, sometimes referred to as staple, of a synthetic polymeric fiber, and cotton fibers. The synthetic polymer or resin of the filament is preferably a polyester. The proportion of the blends can be from percent synthetic fiber and 20 percent cotton to 20 percent synthetic resin fiber and 80 percent cotton. The presently preferred proportions are about 60 percent of polyester fiber and 40 percent of cotton fiber. The weft thread or yarn 14 in the present embodiment is a singles yarn of 21s (the number of 840 yard lengths in 1 pound, according to the cotton number system) having in the greige state a breaking strength of about 1 pound (450 grams) and a twist of approximately 21 turns per inch. Weft yarns may range from 18s to 26: (cotton number system) in the ambit of the present invention.

Weft yarns according to the present invention however are characterized by having in the greige state from about 2 to about 4 times theelongation at break possessed by conventional cotton filling thread of like size and weight. The pick threads 14 have an elongation at break particularly of approximately 3 times the elongation at break of a cotton thread of like size and weight providing a significant improvement over the cotton thread, while the size and softness of the weft yarn according to the invention are at least as satisfactory as conventional weft yarns.

We have found furthermore that our improved filling thread is less subject to longitudinal shrinkage during exposure of the yarn to adhesive solutions and to heat. Our weft or filling thread therefore provides improved resistance against the tendency, experienced with weft or pick threads of the prior art, to cause the cords in the fabric to move closer together during treatment, thus making the fabric more narrow. This tendency, common in pick or weft threads of the prior art, causes adjacent cords to adhere to one another, and/or to form a film or web of adhesive therebetween which, as is known, is detrimental both in the subsequent processing and in the tire in which the fabric is used. The weft yarn according to the invention has sufficient strength to permit handling of the reinforcement fabric during normal processing with greatly reduced breakage of the individual or of successive pick threads, thus In tire cord fabric according to the invention, the fill thread resisting the tendency to split during processing. Furthermore. 14 is broken easily in the shaping of a tire containing the'fabric there appears to be less tendency to slippage at the contacts and is likewise easily handled in the conventional tire building between cords and weft yarns which characteristic appears to operations. In the processing of tire cord fabric, including apimprove further the stability of the fabric, The greater elonga- 5 plication of adhesives, drying, and stretching, the fill thread 14 tion possessed by the yarns 14 not only greatly improves the provides the desired strength, transverse elongation and stashock resistance of the fabric during handling and shipping bility ofthe woven fabric. Fabric containing fill thread accordbut additionally enables increased spreading of the fabric img t th in nti n is moreover significantly less subject to mediately before and immediately after its immersion in adhedamage Such as plitting during processing, or during handling sive solution so as to enable the amount of adhesive applied to and pp g The B ebhgatioh capabhhles P' the be increased, as well as to permit spreading movement tending fahric to be Spread to a greater degree, ehhhhhg improved P- to eparate adjacent ords one from another so as to counpllcat ion Of adhesives avoiding the disadvantages Of teraet the tendency f h adhesive to bridge or web the webbing and adhesion of one cord to the ad acent cords. Con- Spaces between the etude ventional spreading devices acting on the fabric thus provide the table b l representative values f breaking 15 better control of the fabric width as the fabric is advanced strength in pounds (lbs.) avoirdupois and of elongation at through succesive Stages P break, in percent of unstressed length of weft or pick threads whlle Gena! representatlve embodlmehts f f are set forth. in the all-cotton pick threads of the prior art, been shown for the P l oflhushahhg the lhvfihhohr elongation at break is about 5-6 percent. Elongation at break be W to those skllled val'lous changes and modifications may be made therein without departing of the pick threads of synthetic polymeric fiber according to I from the spmt or scope of the invention.

the invention have elongation at break from about 10 percent to about 27 percent. i.e., from 2 to about 4 times the elongawe claim:

tion at break of the all-cotton thread, both being in the greige l In a f i h ing rp rd for reinforcing pneumatic state. Following treatment with adhesive, by di ing, nd with tires and the like, and filling threads for holding the cords in heat (2 minutes at 250F.) the all-cotton thread has elongation sp ced relation, the improvement wherein the filling threads at break of from 3.9 percent to 4.6 percent, while the blended comprise staple fibers of a synthflic p y and cotton fiber threads according to the invention have values of elongabiehded Ogeihel tion at break of from 5.4 percent to 26.6 percent, which is to 2 Th improvement f l im 1. herein th pl fi ers of say from 40 percent to 300 percent greater elongation than. 30 h sy h i p lym r re. by igh fr m 2 to 80 percent of or from about 1% to 3 times the elongation of all-cotton tho ioh'iiweighioflhe filling r dsthread of like size and weight. 3. The improvement of claim I, wherein the staple fibers of Weft Threads of the Weft Threads According to the Present Invention Prior Art Polyester/t otton Blends All-Cotton All Cotton HJ/BO 30170 40/60 60/40 70/30 80/20 60/40 60/40 185 '21s 21s 21s 21s 21s 21s 21s 26s 20s Grelge:

Breakingstrength (ibS.)-.-..- n... 1.06 .01 .77 .81 .87 .87 .00 1.31 .94 1.15 Elongation at Break (pe cent) 6.0 5. 1 11. I 15.6 17.8 17 8 20 4 20. 6 20. 3 23, 7 Dipped, then Dried at 250 F., 2 Minutes:

Breaking Strength (lbs.) 1. 11 .95 .73 75 .81 .80 .02 1.21 .77 1. 07 Elongation at Break (percent) 4. 6 3. 9 5. 4 7. 1 8. l 8. 1 l0. 8 l2. 1 l2. 8 20. 4

As will be seen from the data shown in the table, the breakthe synthetic polymer and cotton are, by weight, about 60 and ing strength of the pick thread or yarn according to the inven- 40 percent, respectively, of the total weight of the filling tion does not differ significantly from the breaking strength of threads.

prior art all-cotton pick threads, namely, from 0.77 to 1.31 4. The improvement of claim I, wherein the filling threads, pounds compared with 0.91 and 1.06 pounds both in the in the greige state, have abreaking strength of from 0.6 to L5 greige condition and from 0.73 to 1.21 pounds compared with pounds and an elongation at break of from 10 percent to 30 0.95 and Li I pounds in the processed condition. The percent.

requisite limits of breaking strength desired for satisfactorily 5. The improvement of claim I, wherein the synthetic severing lengths of ply material and for shaping a tire are polymer is polyester.

achieved while the pick thread or weft of the invention pro- 6. in a fabric having warp cords for reinforcing pneumatic vides improved resistance to splitting and to rupture of the tires and the like, and filling threads for holding the cords in fabric in handling and processing, as well as improved ,spaced relation, the improvement wherein the filling threads spreadability and resistance to webbing. comprise about percent by weight of polyester staple fibers The pick, weft, or filling threads of blended polyester and and about 40 percent by weight of cotton fibers, said filling cotton in accordance with the invention are significantly less 60 threads in the greige state having a breaking strength of from subject to loss of strength and elasticity when wet than the all- I 0.6 to 1.5 pounds and an elongation at break from 10 percent cotton threads heretofore in use. to 30 percent. 

